MAC Exhaust

I also have an old MAC that I'm saving for my second KZ1000A1 rebuild...the pipe is in decent shape and it is old...maybe the older ones were constructed/chromed better than the newer ones?

I can't compare the sound of my Mac with that of a Kerker, but I have ridden with someone with an open Vance and Hines on his KZ1000. Both of our headers were open at the time.
Decibel level seemed to be about the same, but my Mac had a deeper tone than his V&H. Almost made my engine sound bigger than his.

For the money, I like the Mac.

I will probably remove the Mac canister (All steel and heavy) and slip on a kerker or some other aluminum canister.

are all kerker cans aluminum?

9am53 wrote:

are all kerker cans aluminum?

The K series are aluminum...the original style are steel.

I replaced the Kerker on my 76 900 with a MAC and the performance difference was noticeable. The pipe has been on the 900 now for 5 years and it has not fallen apart yet. The headers turned rusty after the paint burned off, but none worst than the Kerker that was on there before. The metal is a bit thinner on the MAC but not so thin that it will burn threw.

I used to have a Kerker many years back on an old Honda 500 four cylinder and I liked it. I have a Vance & Hines on my KZ900 and I just recently put a 1.75" Competition baffle in it. To me the Vance & Hines follows the lines of the bike really well.

I just dropped them an email to see if I can get someone to respond to us. It would be nice if we could get some real information without guessing and implying. Let's hope we get a bite.

When I bought my 76 kz900 it had the stock original head pipes. The four mufflers had been cut off and slip-on LTD pipes installed ( See pictures on July/August trip photos thread ). The insides were totally gone.

I don't, and neither do my neighbours, like loud motorcycles. So I replaced them with MAC slip-ons. Really inexpensive. The chrome is already flaking off the leading edges (which happened on installation). But it sounds pretty good to me and I prefer the 4 into 2 look vs a 4 into 1 header. I'm not looking for more power. It has more than enough to get me into trouble.

The biggest issue for me is centre stand clearance. The 4 into 2 system pushes it down lower than the original 4 into 4, and I regularly scrape the stand on left hand curves.

Also for me to retain Collector Plate status I need to keep it as stock as possible, and 4 into 1 systems were not a stock configuration. I didn't look around all that hard, but MAC was all I could find in a 4 into 2 slip-on.

To sum up, I would buy them again. I may have to. Given the low price of $250 delivered, replacement every few years is no different than replacing a cheap muffler on a car every few years. It's just a cost of maintenance.

I have a black MAC 4->1 on my 750. It was there when bought the bike 7 years ago. I like the deep sound. Not to loud and not to quiet. Solid as a rock and no interferance with the drain plug. I give the header a once over with a wire brush every year followed by a coat of barbecue paint. The canister has never needed even as much as a touch up.

Galactica wrote:

When I bought my 76 kz900 it had the stock original head pipes. The four mufflers had been cut off and slip-on LTD pipes installed ( See pictures on July/August trip photos thread ). The insides were totally gone.

I don't, and neither do my neighbours, like loud motorcycles. So I replaced them with MAC slip-ons. Really inexpensive. The chrome is already flaking off the leading edges (which happened on installation). But it sounds pretty good to me and I prefer the 4 into 2 look vs a 4 into 1 header. I'm not looking for more power. It has more than enough to get me into trouble.

The biggest issue for me is centre stand clearance. The 4 into 2 system pushes it down lower than the original 4 into 4, and I regularly scrape the stand on left hand curves.

Also for me to retain Collector Plate status I need to keep it as stock as possible, and 4 into 1 systems were not a stock configuration. I didn't look around all that hard, but MAC was all I could find in a 4 into 2 slip-on.

To sum up, I would buy them again. I may have to. Given the low price of $250 delivered, replacement every few years is no different than replacing a cheap muffler on a car every few years. It's just a cost of maintenance.

The 4-2 was not stock on the 900 either, so why would it make a difference for the plates since it is not the original 4-4. If it's not stock it is not stock, PERIOD.

I know the 4 into 2 was not stock on the kz900, but it was on the LTD. I am actually allowed to put on headers as well some other modifications that are period correct, but I don't want to take a chance of pissing off the insurance gods at ICBC.

When applying for Collector Plates you have to submit photos so they can do research and accept or reject your application. The photos I submitted showed 4 into 2 and was accepted.

The exceptions listed in ICBC's list of allowable modifications pertain to cars. The relevant ones are headers, a 4 barrel carb but not a hi-rise manifold, and period correct mag wheels. So I guess they deemed the 4 into 2 acceptable.

When dealing with our state owned insurance company, it's best not to press your luck. Especially when Collector insurance is only $230 for the whole year.